Sintering of cubic boron nitride under high pressures and temperatures in the presence of boron carbide as the binding material

摘要

Sintering of cubic boron nitride (cBN) was carried out by subjecting fine powders of cBN to high pressures and temperatures (P = 50-60 kb, T = 1200-1500 deg C ) in the presence of boron carbide as the main binding material together with a small amount of aluminium nitride. The composites were characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman Spectroscopy and microhardness measurements. Best composites with a maximum microhardness of about 3700 kg/mm~2 were obtained at around 50 kb, 1450 deg C using 75 wt percent of cBN in the mixture. No peaks due to hexagonal boron nitride were observed in the XRD patterns.